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+;;; nnselect.el --- a virtual group backend -*- lexical-binding:t -*-
+
+;; Copyright (C) 2020 Free Software Foundation, Inc.
+
+;; Author: Andrew Cohen <cohen@andy.bu.edu>
+;; Keywords: news mail
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This is a "virtual" backend that allows an aribtrary list of
+;; articles to be treated as a gnus group. An nnselect group uses an
+;; nnselect-spec group parameter to specify this list of
+;; articles. nnselect-spec is an alist with two keys:
+;; nnselect-function, whose value should be a function that returns
+;; the list of articles, and nnselect-args. The function will be
+;; applied to the arguments to generate the list of articles. The
+;; return value should be a vector, each element of which should in
+;; turn be a vector of three elements: a real prefixed group name, an
+;; article number in that group, and an integer score. The score is
+;; not used by nnselect but may be used by other code to help in
+;; sorting. Most functions will just chose a fixed number, such as
+;; 100, for this score.
+
+;; For example the search function `nnir-run-query' applied to
+;; arguments specifying a search query (see "nnir.el") can be used to
+;; return a list of articles from a search. Or the function can be the
+;; identity and the args a vector of articles.
+
+
+;;; Code:
+
+;;; Setup:
+
+(require 'gnus-art)
+(require 'nnir)
+
+(eval-when-compile (require 'cl-lib))
+
+;; Set up the backend
+
+(nnoo-declare nnselect)
+
+(nnoo-define-basics nnselect)
+
+(gnus-declare-backend "nnselect" 'post-mail 'virtual)
+
+;;; Internal Variables:
+
+(defvar gnus-inhibit-demon)
+(defvar gnus-message-group-art)
+
+;; For future use
+(defvoo nnselect-directory gnus-directory
+ "Directory for the nnselect backend.")
+
+(defvoo nnselect-active-file
+ (expand-file-name "nnselect-active" nnselect-directory)
+ "nnselect active file.")
+
+(defvoo nnselect-groups-file
+ (expand-file-name "nnselect-newsgroups" nnselect-directory)
+ "nnselect groups description file.")
+
+;;; Helper routines.
+(defun nnselect-compress-artlist (artlist)
+ "Compress ARTLIST."
+ (let (selection)
+ (pcase-dolist (`(,artgroup . ,arts)
+ (nnselect-categorize artlist 'nnselect-artitem-group))
+ (let (list)
+ (pcase-dolist (`(,rsv . ,articles)
+ (nnselect-categorize
+ arts 'nnselect-artitem-rsv 'nnselect-artitem-number))
+ (push (cons rsv (gnus-compress-sequence (sort articles '<)))
+ list))
+ (push (cons artgroup list) selection)))
+ selection))
+
+(defun nnselect-uncompress-artlist (artlist)
+ "Uncompress ARTLIST."
+ (if (vectorp artlist)
+ artlist
+ (let (selection)
+ (pcase-dolist (`(,artgroup (,artrsv . ,artseq)) artlist)
+ (setq selection
+ (vconcat
+ (cl-map 'vector
+ #'(lambda (art)
+ (vector artgroup art artrsv))
+ (gnus-uncompress-sequence artseq)) selection)))
+ selection)))
+
+(defun nnselect-group-server (group)
+ "Return the server for GROUP."
+ (gnus-group-server group))
+
+;; Data type article list.
+
+(define-inline nnselect-artlist-length (artlist)
+ (inline-quote (length ,artlist)))
+
+(define-inline nnselect-artlist-article (artlist n)
+ "Return from ARTLIST the Nth artitem (counting starting at 1)."
+ (inline-quote (when (> ,n 0)
+ (elt ,artlist (1- ,n)))))
+
+(define-inline nnselect-artitem-group (artitem)
+ "Return the group from the ARTITEM."
+ (inline-quote (elt ,artitem 0)))
+
+(define-inline nnselect-artitem-number (artitem)
+ "Return the number from the ARTITEM."
+ (inline-quote (elt ,artitem 1)))
+
+(define-inline nnselect-artitem-rsv (artitem)
+ "Return the Retrieval Status Value (RSV, score) from the ARTITEM."
+ (inline-quote (elt ,artitem 2)))
+
+(define-inline nnselect-article-group (article)
+ "Return the group for ARTICLE."
+ (inline-quote
+ (nnselect-artitem-group (nnselect-artlist-article
+ gnus-newsgroup-selection ,article))))
+
+(define-inline nnselect-article-number (article)
+ "Return the number for ARTICLE."
+ (inline-quote (nnselect-artitem-number
+ (nnselect-artlist-article
+ gnus-newsgroup-selection ,article))))
+
+(define-inline nnselect-article-rsv (article)
+ "Return the rsv for ARTICLE."
+ (inline-quote (nnselect-artitem-rsv
+ (nnselect-artlist-article
+ gnus-newsgroup-selection ,article))))
+
+(define-inline nnselect-article-id (article)
+ "Return the pair `(nnselect id . real id)' of ARTICLE."
+ (inline-quote (cons ,article (nnselect-article-number ,article))))
+
+(define-inline nnselect-categorize (sequence keyfunc &optional valuefunc)
+ "Sorts a sequence into categories.
+Returns a list of the form
+`((key1 (element11 element12)) (key2 (element21 element22))'.
+The category key for a member of the sequence is obtained
+as `(keyfunc member)' and the corresponding element is just
+`member' (or `(valuefunc member)' if `valuefunc' is non-nil)."
+ (inline-letevals (sequence keyfunc valuefunc)
+ (inline-quote (let ((valuefunc (or ,valuefunc 'identity))
+ result)
+ (unless (null ,sequence)
+ (mapc
+ (lambda (member)
+ (let* ((key (funcall ,keyfunc member))
+ (value (funcall valuefunc member))
+ (kr (assoc key result)))
+ (if kr
+ (push value (cdr kr))
+ (push (list key value) result))))
+ (reverse ,sequence))
+ result)))))
+
+
+;; Unclear whether a macro or an inline function is best.
+;; (defmacro nnselect-categorize (sequence keyfunc &optional valuefunc)
+;; "Sorts a sequence into categories and returns a list of the form
+;; `((key1 (element11 element12)) (key2 (element21 element22))'.
+;; The category key for a member of the sequence is obtained
+;; as `(keyfunc member)' and the corresponding element is just
+;; `member' (or `(valuefunc member)' if `valuefunc' is non-nil)."
+;; (let ((key (make-symbol "key"))
+;; (value (make-symbol "value"))
+;; (result (make-symbol "result"))
+;; (valuefunc (or valuefunc 'identity)))
+;; `(unless (null ,sequence)
+;; (let (,result)
+;; (mapc
+;; (lambda (member)
+;; (let* ((,key (,keyfunc member))
+;; (,value (,valuefunc member))
+;; (kr (assoc ,key ,result)))
+;; (if kr
+;; (push ,value (cdr kr))
+;; (push (list ,key ,value) ,result))))
+;; (reverse ,sequence))
+;; ,result))))
+
+(define-inline ids-by-group (articles)
+ (inline-quote
+ (nnselect-categorize ,articles 'nnselect-article-group
+ 'nnselect-article-id)))
+
+(define-inline numbers-by-group (articles)
+ (inline-quote
+ (nnselect-categorize
+ ,articles 'nnselect-article-group 'nnselect-article-number)))
+
+
+(defmacro nnselect-add-prefix (group)
+ "Ensures that the GROUP has an nnselect prefix."
+ `(gnus-group-prefixed-name
+ (gnus-group-short-name ,group) '(nnselect "nnselect")))
+
+(defmacro nnselect-get-artlist (group)
+ "Retrieve the list of articles for GROUP."
+ `(when (gnus-nnselect-group-p ,group)
+ (nnselect-uncompress-artlist
+ (gnus-group-get-parameter ,group 'nnselect-artlist t))))
+
+(defmacro nnselect-add-novitem (novitem)
+ "Add NOVITEM to the list of headers."
+ `(let* ((novitem ,novitem)
+ (artno (and novitem
+ (mail-header-number novitem)))
+ (art (car-safe (rassq artno artids))))
+ (when art
+ (setf (mail-header-number novitem) art)
+ (push novitem headers))))
+
+;;; User Customizable Variables:
+
+(defgroup nnselect nil
+ "Virtual groups in Gnus with arbitrary selection methods."
+ :group 'gnus)
+
+(defcustom nnselect-retrieve-headers-override-function nil
+ "A function that retrieves article headers for ARTICLES from GROUP.
+The retrieved headers should populate the `nntp-server-buffer'.
+Returns either the retrieved header format 'nov or 'headers.
+
+If this variable is nil, or if the provided function returns nil,
+ `gnus-retrieve-headers' will be called instead."
+ :version "24.1" :type '(function) :group 'nnselect)
+
+
+;; Gnus backend interface functions.
+
+(deffoo nnselect-open-server (server &optional definitions)
+ ;; Just set the server variables appropriately.
+ (let ((backend (or (car (gnus-server-to-method server)) 'nnselect)))
+ (nnoo-change-server backend server definitions)))
+
+;; (deffoo nnselect-server-opened (&optional server)
+;; "Is SERVER the current virtual server?"
+;; (if (string-empty-p server)
+;; t
+;; (let ((backend (car (gnus-server-to-method server))))
+;; (nnoo-current-server-p (or backend 'nnselect) server))))
+
+(deffoo nnselect-server-opened (&optional _server)
+ t)
+
+
+(deffoo nnselect-request-group (group &optional _server _dont-check info)
+ (let* ((group (nnselect-add-prefix group))
+ (nnselect-artlist (nnselect-get-artlist group))
+ length)
+ ;; Check for cached select result or run the selection and cache
+ ;; the result.
+ (unless nnselect-artlist
+ (gnus-group-set-parameter
+ group 'nnselect-artlist
+ (nnselect-compress-artlist (setq nnselect-artlist
+ (nnselect-run
+ (gnus-group-get-parameter group 'nnselect-specs t)))))
+ (nnselect-request-update-info
+ group (or info (gnus-get-info group))))
+ (if (zerop (setq length (nnselect-artlist-length nnselect-artlist)))
+ (progn
+ (nnheader-report 'nnselect "Selection produced empty results.")
+ (nnheader-insert ""))
+ (with-current-buffer nntp-server-buffer
+ (nnheader-insert "211 %d %d %d %s\n"
+ length ; total #
+ 1 ; first #
+ length ; last #
+ group))) ; group name
+ nnselect-artlist))
+
+
+(deffoo nnselect-retrieve-headers (articles group &optional _server fetch-old)
+ (let ((group (nnselect-add-prefix group)))
+ (with-current-buffer (gnus-summary-buffer-name group)
+ (setq gnus-newsgroup-selection (or gnus-newsgroup-selection
+ (nnselect-get-artlist group)))
+ (let ((gnus-inhibit-demon t)
+ (gartids (ids-by-group articles))
+ headers)
+ (with-current-buffer nntp-server-buffer
+ (pcase-dolist (`(,artgroup . ,artids) gartids)
+ (let ((artlist (sort (mapcar 'cdr artids) '<))
+ (gnus-override-method (gnus-find-method-for-group artgroup))
+ (fetch-old
+ (or
+ (car-safe
+ (gnus-group-find-parameter artgroup
+ 'gnus-fetch-old-headers t))
+ fetch-old)))
+ (erase-buffer)
+ (pcase (setq gnus-headers-retrieved-by
+ (or
+ (and
+ nnselect-retrieve-headers-override-function
+ (funcall
+ nnselect-retrieve-headers-override-function
+ artlist artgroup))
+ (gnus-retrieve-headers
+ artlist artgroup fetch-old)))
+ ('nov
+ (goto-char (point-min))
+ (while (not (eobp))
+ (nnselect-add-novitem
+ (nnheader-parse-nov))
+ (forward-line 1)))
+ ('headers
+ (goto-char (point-min))
+ (while (not (eobp))
+ (nnselect-add-novitem
+ (nnheader-parse-head))
+ (forward-line 1)))
+ ((pred listp)
+ (dolist (novitem gnus-headers-retrieved-by)
+ (nnselect-add-novitem novitem)))
+ (_ (error "Unknown header type %s while requesting articles \
+ of group %s" gnus-headers-retrieved-by artgroup)))))
+ (setq headers
+ (sort
+ headers
+ (lambda (x y)
+ (< (mail-header-number x) (mail-header-number y))))))))))
+
+
+(deffoo nnselect-request-article (article &optional _group server to-buffer)
+ (let* ((gnus-override-method nil)
+ servers group-art artlist)
+ (if (numberp article)
+ (with-current-buffer gnus-summary-buffer
+ (unless (zerop (nnselect-artlist-length
+ gnus-newsgroup-selection))
+ (setq group-art (cons (nnselect-article-group article)
+ (nnselect-article-number article)))))
+ ;; message-id: either coming from a referral or a pseudo-article
+ ;; find the servers for a pseudo-article
+ (if (eq 'nnselect (car (gnus-server-to-method server)))
+ (with-current-buffer gnus-summary-buffer
+ (let ((thread (gnus-id-to-thread article)))
+ (when thread
+ (mapc
+ #'(lambda (x)
+ (when (and x (> x 0))
+ (cl-pushnew
+ (list
+ (gnus-method-to-server
+ (gnus-find-method-for-group
+ (nnselect-article-group x)))) servers :test 'equal)))
+ (gnus-articles-in-thread thread)))))
+ (setq servers (list (list server))))
+ (setq artlist
+ (nnir-run-query
+ (list
+ (cons 'nnir-query-spec
+ (list (cons 'query (format "HEADER Message-ID %s" article))
+ (cons 'criteria "") (cons 'shortcut t)))
+ (cons 'nnir-group-spec servers))))
+ (unless (zerop (nnselect-artlist-length artlist))
+ (setq
+ group-art
+ (cons
+ (nnselect-artitem-group (nnselect-artlist-article artlist 1))
+ (nnselect-artitem-number (nnselect-artlist-article artlist 1))))))
+ (when (numberp (cdr group-art))
+ (message "Requesting article %d from group %s"
+ (cdr group-art) (car group-art))
+ (if to-buffer
+ (with-current-buffer to-buffer
+ (let ((gnus-article-decode-hook nil))
+ (gnus-request-article-this-buffer
+ (cdr group-art) (car group-art))))
+ (gnus-request-article (cdr group-art) (car group-art)))
+ group-art)))
+
+
+(deffoo nnselect-request-move-article
+ (article _group _server accept-form &optional last _internal-move-group)
+ (let* ((artgroup (nnselect-article-group article))
+ (artnumber (nnselect-article-number article))
+ (to-newsgroup (nth 1 accept-form))
+ (to-method (gnus-find-method-for-group to-newsgroup))
+ (from-method (gnus-find-method-for-group artgroup))
+ (move-is-internal (gnus-server-equal from-method to-method)))
+ (unless (gnus-check-backend-function
+ 'request-move-article artgroup)
+ (error "The group %s does not support article moving" artgroup))
+ (gnus-request-move-article
+ artnumber
+ artgroup
+ (nth 1 from-method)
+ accept-form
+ last
+ (and move-is-internal
+ to-newsgroup ; Not respooling
+ (gnus-group-real-name to-newsgroup)))))
+
+
+(deffoo nnselect-request-expire-articles
+ (articles _group &optional _server force)
+ (if force
+ (let (not-expired)
+ (pcase-dolist (`(,artgroup . ,artids) (ids-by-group articles))
+ (let ((artlist (sort (mapcar 'cdr artids) '<)))
+ (unless (gnus-check-backend-function 'request-expire-articles
+ artgroup)
+ (error "Group %s does not support article expiration" artgroup))
+ (unless (gnus-check-server (gnus-find-method-for-group artgroup))
+ (error "Couldn't open server for group %s" artgroup))
+ (push (mapcar #'(lambda (art)
+ (car (rassq art artids)))
+ (let ((nnimap-expunge 'immediately))
+ (gnus-request-expire-articles
+ artlist artgroup force)))
+ not-expired)))
+ (sort (delq nil not-expired) '<))
+ articles))
+
+
+(deffoo nnselect-warp-to-article ()
+ (let* ((cur (if (> (gnus-summary-article-number) 0)
+ (gnus-summary-article-number)
+ (error "Can't warp to a pseudo-article")))
+ (artgroup (nnselect-article-group cur))
+ (artnumber (nnselect-article-number cur))
+ (_quit-config (gnus-ephemeral-group-p gnus-newsgroup-name)))
+
+ ;; what should we do here? we could leave all the buffers around
+ ;; and assume that we have to exit from them one by one. or we can
+ ;; try to clean up directly
+
+ ;;first exit from the nnselect summary buffer.
+ ;;(gnus-summary-exit)
+ ;; and if the nnselect summary buffer in turn came from another
+ ;; summary buffer we have to clean that summary up too.
+ ;;(when (not (eq (cdr quit-config) 'group))
+ ;; (gnus-summary-exit))
+ (gnus-summary-read-group-1 artgroup t t nil
+ nil (list artnumber))))
+
+
+;; we pass this through to the real group in case it wants to adjust
+;; the mark. We also use this to mark an article expirable iff it is
+;; expirable in the real group.
+(deffoo nnselect-request-update-mark (_group article mark)
+ (let* ((artgroup (nnselect-article-group article))
+ (artnumber (nnselect-article-number article))
+ (gmark (gnus-request-update-mark artgroup artnumber mark)))
+ (when (and artnumber
+ (memq mark gnus-auto-expirable-marks)
+ (= mark gmark)
+ (gnus-group-auto-expirable-p artgroup))
+ (setq gmark gnus-expirable-mark))
+ gmark))
+
+
+(deffoo nnselect-request-set-mark (_group actions &optional _server)
+ (mapc
+ (lambda (request) (gnus-request-set-mark (car request) (cdr request)))
+ (nnselect-categorize
+ (cl-mapcan
+ (lambda (act)
+ (cl-destructuring-bind (range action marks) act
+ (mapcar
+ (lambda (artgroup)
+ (list (car artgroup)
+ (gnus-compress-sequence (sort (cdr artgroup) '<))
+ action marks))
+ (numbers-by-group
+ (gnus-uncompress-range range)))))
+ actions)
+ 'car 'cdr)))
+
+(deffoo nnselect-request-update-info (group info &optional _server)
+ (let* ((group (nnselect-add-prefix group))
+ (gnus-newsgroup-selection (or gnus-newsgroup-selection
+ (nnselect-get-artlist group))))
+ (gnus-info-set-marks info nil)
+ (setf (gnus-info-read info) nil)
+ (pcase-dolist (`(,artgroup . ,nartids)
+ (ids-by-group
+ (number-sequence 1 (nnselect-artlist-length
+ gnus-newsgroup-selection))))
+ (let* ((gnus-newsgroup-active nil)
+ (artids (cl-sort nartids '< :key 'car))
+ (group-info (gnus-get-info artgroup))
+ (marks (gnus-info-marks group-info))
+ (unread (gnus-uncompress-sequence
+ (gnus-range-difference (gnus-active artgroup)
+ (gnus-info-read group-info)))))
+ (gnus-atomic-progn
+ (setf (gnus-info-read info)
+ (gnus-add-to-range
+ (gnus-info-read info)
+ (delq nil
+ (mapcar
+ #'(lambda (art)
+ (unless (memq (cdr art) unread) (car art)))
+ artids))))
+ (pcase-dolist (`(,type . ,range) marks)
+ (setq range (gnus-uncompress-sequence range))
+ (gnus-add-marked-articles
+ group type
+ (delq nil
+ (mapcar
+ #'(lambda (art)
+ (when (memq (cdr art) range)
+ (car art))) artids)))))))
+ (gnus-set-active group (cons 1 (nnselect-artlist-length
+ gnus-newsgroup-selection)))))
+
+
+(deffoo nnselect-request-thread (header &optional group server)
+ (with-current-buffer gnus-summary-buffer
+ (let ((group (nnselect-add-prefix group))
+ ;; find the best group for the originating article. if its a
+ ;; pseudo-article look for real articles in the same thread
+ ;; and see where they come from.
+ (artgroup (nnselect-article-group
+ (if (> (mail-header-number header) 0)
+ (mail-header-number header)
+ (if (> (gnus-summary-article-number) 0)
+ (gnus-summary-article-number)
+ (let ((thread
+ (gnus-id-to-thread (mail-header-id header))))
+ (when thread
+ (cl-some #'(lambda (x)
+ (when (and x (> x 0)) x))
+ (gnus-articles-in-thread thread)))))))))
+ ;; Check if we are dealing with an imap backend.
+ (if (eq 'nnimap
+ (car (gnus-find-method-for-group artgroup)))
+ ;; If so we perform the query, massage the result, and return
+ ;; the new headers back to the caller to incorporate into the
+ ;; current summary buffer.
+ (let* ((group-spec
+ (list (delq nil (list
+ (or server (gnus-group-server artgroup))
+ (unless gnus-refer-thread-use-search
+ artgroup)))))
+ (query-spec
+ (list (cons 'query (nnimap-make-thread-query header))
+ (cons 'criteria "")))
+ (last (nnselect-artlist-length gnus-newsgroup-selection))
+ (first (1+ last))
+ (new-nnselect-artlist
+ (nnir-run-query
+ (list (cons 'nnir-query-spec query-spec)
+ (cons 'nnir-group-spec group-spec))))
+ old-arts seq
+ headers)
+ (mapc
+ #'(lambda (article)
+ (if
+ (setq seq
+ (cl-position article
+ gnus-newsgroup-selection :test 'equal))
+ (push (1+ seq) old-arts)
+ (setq gnus-newsgroup-selection
+ (vconcat gnus-newsgroup-selection (vector article)))
+ (cl-incf last)))
+ new-nnselect-artlist)
+ (setq headers
+ (gnus-fetch-headers
+ (append (sort old-arts '<)
+ (number-sequence first last)) nil t))
+ (gnus-group-set-parameter
+ group
+ 'nnselect-artlist
+ (nnselect-compress-artlist gnus-newsgroup-selection))
+ (when (>= last first)
+ (let (new-marks)
+ (pcase-dolist (`(,artgroup . ,artids)
+ (ids-by-group (number-sequence first last)))
+ (pcase-dolist (`(,type . ,marked)
+ (gnus-info-marks (gnus-get-info artgroup)))
+ (setq marked (gnus-uncompress-sequence marked))
+ (when (setq new-marks
+ (delq nil
+ (mapcar
+ #'(lambda (art)
+ (when (memq (cdr art) marked)
+ (car art)))
+ artids)))
+ (nconc
+ (symbol-value
+ (intern
+ (format "gnus-newsgroup-%s"
+ (car (rassq type gnus-article-mark-lists)))))
+ new-marks)))))
+ (setq gnus-newsgroup-active
+ (cons 1 (nnselect-artlist-length gnus-newsgroup-selection)))
+ (gnus-set-active
+ group
+ (cons 1 (nnselect-artlist-length gnus-newsgroup-selection))))
+ headers)
+ ;; If not an imap backend just warp to the original article
+ ;; group and punt back to gnus-summary-refer-thread.
+ (and (gnus-warp-to-article) (gnus-summary-refer-thread))))))
+
+
+(deffoo nnselect-close-group (group &optional _server)
+ (let ((group (nnselect-add-prefix group)))
+ (unless gnus-group-is-exiting-without-update-p
+ (nnselect-push-info group))
+ (setq gnus-newsgroup-selection nil)
+ (when (gnus-ephemeral-group-p group)
+ (gnus-kill-ephemeral-group group)
+ (setq gnus-ephemeral-servers
+ (assq-delete-all 'nnselect gnus-ephemeral-servers)))))
+
+
+(deffoo nnselect-request-create-group (group &optional _server args)
+ (message "Creating nnselect group %s" group)
+ (let* ((group (gnus-group-prefixed-name group '(nnselect "nnselect")))
+ (specs (assq 'nnselect-specs args))
+ (function-spec
+ (or (alist-get 'nnselect-function specs)
+ (intern (completing-read "Function: " obarray #'functionp))))
+ (args-spec
+ (or (alist-get 'nnselect-args specs)
+ (read-from-minibuffer "Args: " nil nil t nil "nil")))
+ (nnselect-specs (list (cons 'nnselect-function function-spec)
+ (cons 'nnselect-args args-spec))))
+ (gnus-group-set-parameter group 'nnselect-specs nnselect-specs)
+ (gnus-group-set-parameter
+ group 'nnselect-artlist
+ (nnselect-compress-artlist (or (alist-get 'nnselect-artlist args)
+ (nnselect-run nnselect-specs))))
+ (nnselect-request-update-info group (gnus-get-info group)))
+ t)
+
+
+(deffoo nnselect-request-type (_group &optional article)
+ (if (and (numberp article) (> article 0))
+ (gnus-request-type
+ (nnselect-article-group article) (nnselect-article-number article))
+ 'unknown))
+
+(deffoo nnselect-request-post (&optional _server)
+ (if (not gnus-message-group-art)
+ (nnheader-report 'nnselect "Can't post to an nnselect group")
+ (gnus-request-post
+ (gnus-find-method-for-group
+ (nnselect-article-group (cdr gnus-message-group-art))))))
+
+
+(deffoo nnselect-request-rename-group (_group _new-name &optional _server)
+ t)
+
+
+(deffoo nnselect-request-scan (group _method)
+ (when (and group
+ (gnus-group-get-parameter (nnselect-add-prefix group)
+ 'nnselect-rescan t))
+ (nnselect-request-group-scan group)))
+
+
+(deffoo nnselect-request-group-scan (group &optional _server _info)
+ (let* ((group (nnselect-add-prefix group))
+ (artlist (nnselect-run
+ (gnus-group-get-parameter group 'nnselect-specs t))))
+ (gnus-set-active group (cons 1 (nnselect-artlist-length
+ artlist)))
+ (gnus-group-set-parameter
+ group 'nnselect-artlist
+ (nnselect-compress-artlist artlist))))
+
+;; Add any undefined required backend functions
+
+;; (nnoo-define-skeleton nnselect)
+
+;;; Util Code:
+
+(defun gnus-nnselect-group-p (group)
+ "Say whether GROUP is nnselect or not."
+ (or (and (gnus-group-prefixed-p group)
+ (eq 'nnselect (car (gnus-find-method-for-group group))))
+ (eq 'nnselect (car gnus-command-method))))
+
+
+(defun nnselect-run (specs)
+ "Apply nnselect-function to nnselect-args from SPECS.
+Return an article list."
+ (let ((func (alist-get 'nnselect-function specs))
+ (args (alist-get 'nnselect-args specs)))
+ (funcall func args)))
+
+
+(defun nnselect-search-thread (header)
+ "Make an nnselect group containing the thread with article HEADER.
+The current server will be searched. If the registry is
+installed, the server that the registry reports the current
+article came from is also searched."
+ (let* ((query
+ (list (cons 'query (nnimap-make-thread-query header))
+ (cons 'criteria "")))
+ (server
+ (list (list (gnus-method-to-server
+ (gnus-find-method-for-group gnus-newsgroup-name)))))
+ (registry-group (and
+ (bound-and-true-p gnus-registry-enabled)
+ (car (gnus-registry-get-id-key
+ (mail-header-id header) 'group))))
+ (registry-server
+ (and registry-group
+ (gnus-method-to-server
+ (gnus-find-method-for-group registry-group)))))
+ (when registry-server (cl-pushnew (list registry-server) server
+ :test 'equal))
+ (gnus-group-read-ephemeral-group
+ (concat "nnselect-" (message-unique-id))
+ (list 'nnselect "nnselect")
+ nil
+ (cons (current-buffer) gnus-current-window-configuration)
+ ; nil
+ nil nil
+ (list
+ (cons 'nnselect-specs
+ (list
+ (cons 'nnselect-function 'nnir-run-query)
+ (cons 'nnselect-args
+ (list (cons 'nnir-query-spec query)
+ (cons 'nnir-group-spec server)))))
+ (cons 'nnselect-artlist nil)))
+ (gnus-summary-goto-subject (gnus-id-to-article (mail-header-id header)))))
+
+
+
+(defun nnselect-push-info (group)
+ "Copy mark-lists from GROUP to the originating groups."
+ (let ((select-unreads (numbers-by-group gnus-newsgroup-unreads))
+ (select-reads (numbers-by-group
+ (gnus-uncompress-range
+ (gnus-info-read (gnus-get-info group)))))
+ (select-unseen (numbers-by-group gnus-newsgroup-unseen))
+ (gnus-newsgroup-active nil)
+ mark-list type-list)
+ (pcase-dolist (`(,mark . ,type) gnus-article-mark-lists)
+ (when (setq type-list
+ (symbol-value (intern (format "gnus-newsgroup-%s" mark))))
+ (push (cons type
+ (numbers-by-group
+ (gnus-uncompress-range type-list))) mark-list)))
+ (pcase-dolist (`(,artgroup . ,artlist)
+ (numbers-by-group gnus-newsgroup-articles))
+ (let* ((group-info (gnus-get-info artgroup))
+ (old-unread (gnus-list-of-unread-articles artgroup))
+ newmarked)
+ (when group-info
+ (pcase-dolist (`(,_mark . ,type) gnus-article-mark-lists)
+ (let ((select-type
+ (sort
+ (cdr (assoc artgroup (alist-get type mark-list)))
+ '<)) list)
+ (setq list
+ (gnus-uncompress-range
+ (gnus-add-to-range
+ (gnus-remove-from-range
+ (alist-get type (gnus-info-marks group-info))
+ artlist)
+ select-type)))
+
+ (when list
+ ;; Get rid of the entries of the articles that have the
+ ;; default score.
+ (when (and (eq type 'score)
+ gnus-save-score
+ list)
+ (let* ((arts list)
+ (prev (cons nil list))
+ (all prev))
+ (while arts
+ (if (or (not (consp (car arts)))
+ (= (cdar arts) gnus-summary-default-score))
+ (setcdr prev (cdr arts))
+ (setq prev arts))
+ (setq arts (cdr arts)))
+ (setq list (cdr all)))))
+
+ (when (or (eq (gnus-article-mark-to-type type) 'list)
+ (eq (gnus-article-mark-to-type type) 'range))
+ (setq list
+ (gnus-compress-sequence (sort list '<) t)))
+
+ ;; When exiting the group, everything that's previously been
+ ;; unseen is now seen.
+ (when (eq type 'seen)
+ (setq list (gnus-range-add
+ list (cdr (assoc artgroup select-unseen)))))
+
+ (when (or list (eq type 'unexist))
+ (push (cons type list) newmarked))))
+
+ (gnus-atomic-progn
+ ;; Enter these new marks into the info of the group.
+ (if (nthcdr 3 group-info)
+ (setcar (nthcdr 3 group-info) newmarked)
+ ;; Add the marks lists to the end of the info.
+ (when newmarked
+ (setcdr (nthcdr 2 group-info) (list newmarked))))
+
+ ;; Cut off the end of the info if there's nothing else there.
+ (let ((i 5))
+ (while (and (> i 2)
+ (not (nth i group-info)))
+ (when (nthcdr (cl-decf i) group-info)
+ (setcdr (nthcdr i group-info) nil))))
+
+ ;; update read and unread
+ (gnus-update-read-articles
+ artgroup
+ (gnus-uncompress-range
+ (gnus-add-to-range
+ (gnus-remove-from-range
+ old-unread
+ (cdr (assoc artgroup select-reads)))
+ (sort (cdr (assoc artgroup select-unreads)) '<))))
+ (gnus-get-unread-articles-in-group
+ group-info (gnus-active artgroup) t)
+ (gnus-group-update-group artgroup t t)))))))
+
+
+(declare-function gnus-registry-get-id-key "gnus-registry" (id key))
+
+(defun gnus-summary-make-search-group (nnir-extra-parms)
+ "Search a group from the summary buffer.
+Pass NNIR-EXTRA-PARMS on to the search engine."
+ (interactive "P")
+ (gnus-warp-to-article)
+ (let ((spec
+ (list
+ (cons 'nnir-group-spec
+ (list (list
+ (gnus-group-server gnus-newsgroup-name)
+ gnus-newsgroup-name))))))
+ (gnus-group-make-search-group nnir-extra-parms spec)))
+
+
+;; The end.
+(provide 'nnselect)
+
+;;; nnselect.el ends here